<!DOCTYPE html>
<html lang="en">
    <head>
        <meta charset="UTF-8"/>
        <meta name="viewport" content="width=device-width, initial-scale=1.0"/>
        <meta http-equiv="X-UA-Compatible" content="ie=edge"/>
        <title>Document</title>
        <script src = 'jquery-1.10.1.min.js'></script>
        <script>
            /* 
                addClass()
                removeClass()

                【注】操作class属性
             */
            $(function(){
                // $("#div1").addClass("box3 box4 box2");

                $("#div1").removeClass("box2 box3");
            })
        </script>
    </head>
    <body>
        <div id = 'div1' class = 'box1 box2'></div>
    </body>
</html>